Knot-tying apparatus



Nov. 17, 1959 G. SACHSENRQDER, sR., EI'AL 2,913,270

KNOT-TYING APPARATUS Filed Nov. 30, 1955 v 2 Sheets-Sheet 1 INVEN TORS.Gustav $ackselzriieqfig By Theodor .fckraizez' Wax-1% Nov. 17, 1959 G.SACHS'ENRODER, sR., ETAL 2,913,270

KNOT-TYING APPARATUS F iled Nov. 50, 1955 2 Sheets-Sheet 2 INVENTQRS'.

Gusfav .S'ac/zfienrafcg '1: y Ybeodar Scmder 2,913,210 KNOT-TYINGAPPARATUS Gustav Sachs'enriider, S12, Wuppertal-Barmen, and TheodorSchriider, Wuppertal-Beyenburg, Germany Application November 30, *1955,Serial No. 550,162

Claims priority, application Germany December 13, 1954 10 Claims. (Cl.289-2) This invention relates to an apparatus for making knots withthreads, strings, cords, or the like.

It has already been suggested to use a loop-shaped tubing for knot-tyingpurposes. The tubing was formed to conform to a position which theflexible object used to tie a knot assumes prior to the actual formationof the knot. This position is assumed by the flexible object previous tobeing drawn taut in order to joint together the parts of the flexibleobject, which are involved in the formation of the knot. The tubingreceives the flexible object lengthwise and is slitted along its innerperiphery. The knot is tied by pulling at both ends of the flexibleobject within the loop-shaped tubing. In the known devices of this kind,the flexible object, for instance, a

thread, is inserted in the loop-shaped tubing by introducing it first ina coil spring and then pushing the coil spring through the tubing. Thefree end of the thread emerging at the other end of the tubing is held,and the coil spring is removed from the tubing. On pulling the end ofthe portion of the thread, that is within the tubing, that portionpasses through the slit of the tubing to be laid and tightened aroundany goods within the loop or loops of the tubing. In practice, thepassing and returning of the coil spring through the loops requiresconsiderable time and also causes the sliding parts to wear ofi quickly,the latter effect being due tomechanical friction. Besides, aninconvenience often occurs inasmuch as the free end of the thread tendsto slip into the coil spring, which free end is then difficultly pulledout again. Associated with such inconveniences are interruptions in theoperation and losses of time. The shortcomings of the prior devicesrender it impossible to make packages, to tie sausage casing, to closesacks, bags, or the like in an economical way.

Our present invention aims, therefore, at simplifying the mechanicalformation of knots, speeding up the knotforming actions, avoidingdisturbances and breakdowns, and at rendering the mechanical knot-tyingmore economical. To the accomplishment of the foregoing and otherobjects which will appear hereinafter, our invention consists in theapparatus elements and their relation one to the other, as are moreparticularly described in the specification and sought to be defined inthe claims.

The specification is accompanied by drawings in which:

Fig. 1 schematically illustrates a knot-forming mechanism proper andassociated vacuum pump and guides for the flexible object used to tieknots;

Fig. 2 shows the knot-forming mechanism and guides of Fig. 1 to enlargedscale;

Fig. 3 is a fragmentary cross section through a knotforming mechanism;

Fig. 4 is a fragmentary cross section through a modified knot-formingmechanism;

Fig. 5 illustrates a modification of a knot-forming mechanism; and

Fig. 6 illustrates still another modification of a knotformingmechanism.

Referring to the drawings, and initially to Figs; 1 and 2, theknot-forming mechanism proper consists of a loop-shaped tubingdesignated 1. The tubing 1 is shaped to conform to the open or embryoposition which the flexible object or the thread 6 assumes prior tobeing drawn taut to actually form the intended knot. The flexible objectwhich may be a thread or any kind of twine, a cord, wire, band, gut, aplastic filament or thread of two or more strands twisted together, etc.passes through the loop-shaped tubing. The thread 6 is fed through aguide tube 4 to enter the tubing 1 at its entrance 2. The free end ofthe thread leaves the tubing 1 at its exit 3, where the tube 5 receivessaid free end and acts as a guide. Both tubes are supported in guidesleeves 13 to be axially movable. The tube 5 is connected to a vacuumpump 7 by means of a hose 14.

In the embodiment selected for illustration, as shown in Figs. 1 and 2,the tubing is shaped to deliver a simple knot. The tubing includes anintermediate loop portion, the corresponding thread part of which, upondrawing the thread 6 taut, will press upon the knot formed and preventunintentional untying.

The object 16 to be tied is shown in phantom and is moved through thetying station in thedirection of the line x. i

It will be understood that the knot-tying action of the flexible objectmay start from different open positions. Accordingly, the loop or loopsof the knot-forming mechanism proper may have different radii. The loopsare given a radius r (see Fig. 2) which will correspond to themeasurements of the goods to be passed through the loop for tying.

For the tubing 1, a slitted tube is used. The tubing is shaped to formtwo complete convolutions, and so that the slit 8 will appear along theinner peripheries of the loops. Thus, it is possible for the thread 6,when a pull is exerted on both ends thereof, to be drawn together and toemerge from the tubing through the slit 8. The slit is provided in awidth which will ensure that the flexible object used may passtherethrough without obstruction.

The tubing may be given any suitable shape which corresponds to the openor embryo position of the intended knot, provided that the knot issimply formed by pulling the ends of the flexible object relativelyapart.

The vacuum pump 7, according to our invention, sucks air through thetubing 1 and thus pulls the free end of the thread 6 in the suckingdirection. It is obvious that any gas may be used instead of air andthat the fluid current may be produced by drawing the transportingmedium as well as by blowing same through the tubing.

To obtain a strong fluid current and to keep vacuum or pressure lossesat a minimum, and in order to ensure that the flexible object be quicklyand reliably transported through the loops of the tubing, we provide acover for the'slit in the tubing. Having reference to Fig. 3, 1 is aloop of a knot-forming mechanism, along the inner periphery of whichloop a slit 8 is incised to allow the flexible object 6, for instance, astring, to slip therethrough. The slit is of a width b. A band 9 ofrubber or similar resilient material is secured along, and on one sideof, the slit. The band 9 acts in the manner of a flap valve. outersurface of the loop 1' or fastened thereto by means of clasps 10. InFig. 4, a sleeve 11 of rubber or similar resilient material is shownwhich is longitudinally slitted at 12 and which surrounds the loop 1" tocover the 8", respectively, and to permit at the same time the- It maybe cemented to the flexible object to pass through the slit when theflexible object is tightened to form the knot.

Reverting to Fig. 2, the ends 2 and 3 of the tubing 1 are a distance afrom each other so that the part of the thread 6, that emerges from theportion of the tubing, running obliquely with respect to the guide tubes4 and 5, can actually continue without being caught by the ends 2 and 3.It is advantageous to provide sliding and guide means (not shown) at ornear the ends of the loopshaped tubing in order to assist the flexibleobject in its movement through the slit. Preferably, the end portions ofthe tubing are parallel, and the very ends of these end portions arefunnel-shaped. Coaxially with the end portions at the ends 2 and 3, andjoined thereto, extends the tapered end portion of the tubes 4 and 5,respectively. Each of the tapered end portions fits accurately into afunnel-shaped end of the tubing 1 so that the tubes 4 and 5 are coupledwith the tubing in an airtight although loose fashion. The tubes 4 and 5are longitudinally or axially movable. They are shown to be supported inguide sleeves 13 but may be supported in slides, circular guides aswell.

The length l and the bore (1 of the guide-in tube are adjusted one tothe other. We have found that the shorter the tube 4 is the tighter hasits bore to surround the flexible object. It is, therefore, advisablenot to provide a guide-in tube which is too short since threads andcords are frequently nonuniform in cross section and thickened portionsin flexible objects must be reckoned with. Such nonuniformity, however,is insignificant if, with a suflicient length l of the guide-in tube 4,the latter can be given a diameter which will ensure a greater play forthe flexible object so that thickened portions and the irregularitiesmay readily be sucked through the bore.

The guide-out tube 5 which is joined to the exit end 3 of the tubing 1is likewise coaxially arranged with respect to the end portion of thetubing 1 at 3. The tube 5 makes it possible to provide a long enough endof the flexible object, and to conveniently tie the knot. In the case ofthe tube 5, there is no interdependence as far as bore of the tube,thickness of the flexible object, and length of the tube are concerned.Like the guide-in tube, the guideout or guide-off tube is longitudinallymovable. It may be connected over a flexible hose 14 to the inlet sideof the vacuum pump '7.

To start operation, that is, to produce a knot with the aid of theapparatus of our invention, a flexible object, such as the thread 6, isintroduced into the bore of the guide-in tube. The tube is movedlongitudinally until its tapered end comes to lie within thefunnelshaped end 2 of the tubing 1. case of the tube 5 or guide-outtube, as has already been pointed out, an airtight connection isachieved. Next, the vacuum pump 7 which is connected to the guide-outtube over the hose '14 is started to operate briefly or permanently. Ifthe vacuum pump operates uninterruptedly, a stop valve which may beprovided at any place between the guide-off tube and the vacuum pump isopened for a brief period of action. In whatever Way the vacuum pump ismade to become effective, during that brief period of time, apredetermined length of the flexible object used is sucked through thetube 4 as far as the tube 5. i

In the construction shown, for instance, in Fig. 3, due

to the vacuum produced in the line, the resilient band 9 is tightlypressed against the edges of the slit 8' in the tubing 1, making itimpossible for the air to enter in any Way other than through theguide-in tube holding the flexible object or thread 6. The thread 6 issimilarly pushed forward as a piston in a cylinder.

Prior or during the movement of the flexible object, the goods to betied, identified by the numeral 16 in Fig. 1, are fed into the spacewithin-the tubing l. To tie the knot, all that is still needed is a pullto be applied to the thread 6 at both ends. This may, for instance,

Here as wellas in the I be accomplished by fastening one end to the tube4 and one end to the tube 5, and axially moving the tubes in oppositedirection. In this manner, the embryo knot of the thread will be tiedtautly around the piece of the goods involved. Then the thread is cutoff, the tied piece 16 removed, and the apparatus is ready for a newknot-tying action.

In the construction shown in Fig. 5, the tubes 4a and 5a are rigidlyconnected to the tubing 1a. However, the whole knot-forming mechanism issplit into two sections A and B in a plane shown in the constructionselected for illustration to be perpendicular to the tubes 4:: and 5a.The two sections A and B are made to be movable toward and from eachother. At the connecting points 17, the ends of the tubes 4a and 5a aretapered, and the ends of the tubing 1a are funnel-shaped, similar to theformations shown in Figs. 1 and 2. The operation of the form ofapparatus, shown in Fig. 5, and the knotformation are similar to whathas been described hereinbefore. In view of the provision of theknot-forming mechanism in two sections, and the movability of thesections, it is possible to design the two sections so as to serve asmeans to grab the goods to be tied, for instance, sheaves.

According to another feature of the invention, two or more flexibleobjects, such as threads, are used instead of a single flexible object.In Fig. 6, a construction is shown in which two equally thick threads 18and 19 are to be tied to form a kind of reef knot. Equal thickness ofthe flexible objects, however, is not required since the two devices 112and 1b and the respective associated guide tubes may as well be designedto suit different thicknesses. The guide-in tube 41) and guide-off tube5b are parallel and arranged to be movable relative to the ends of thetubing 1b. The tubes 4b and 5b are similarly arranged with respect tothe tubing 1b. Each of the tubings 1b and 1b, shown in plan view, isformed by a single semicircular or horseshoelike lengthwise slittedloop, the open ends of which are located so as to make sure that theflexible object is carried therethrough by an angle of at least Theloops of the two tubings, with their slitted sides, are so interlaidthat upon pulling the ends of each of the threads 18 and 19, the threadswill leave the slits and finally be tied together to form the referredto type of reef knot. The mode of operation, as far as each of the twotubings 1b and 1b is concerned, and the occurrences during the tying ofthe knot correspond to the actions described with respect to Figs. 1 and2.

The apparatus of our invention can be equipped with means to carry outall the steps involved automatically, such as, the introduction of theflexible object, its passage through the apparatus, the clamping,tightening, and cutting-off of the flexible object, and the feeding ofthe goods to be tied. Provision is made to perform all these steps inproper and continuous succession.

Our apparatus can be designed for intermittent as well as continuousfeed of the goods to be tied. Goods to be tied in our apparatus are, forinstance, sacks, bags, bales, parcels, bundles, natural and syntheticcasings enclosing sausage meats, etc. In addition to tying a hose, theapparatus according to our invention can also be used to wind a cord orthe like around a hose.

As media to transport flexible objects through the knottying apparatus,air or any other gas may be used. To prevent a gaseous medium fromentering through the slit in the loop-shaped tubing, when working undervacuum, or to prevent a transporting pressure medium from escapingthrough the slit, it is also possible to provide a sleevelike valve andto arrange for same to be moved in the direction of the axis x (Fig. 2)to close the slit, and to be withdrawn upon the introduction of thepackage to be tied and prior to tying, thus making it possible for theflexible object to leave the loop-shaped tubing through the slit.

Itis believed that the construction and operation of the apparatus, andthe many advantages thereof, will be fully understood from the foregoingdetailed description. In reviewing some of the features of theinvention, it is pointed out that a gaseous medium is used to transportthe flexible object through the loop-shaped tubing. The loop-shapedtubing may comprise one or more loops and is slitted along its innerperiphery. In order to decrease flow losses and to increase theefliciency of the apparatus, a cover is provided to close the slit in anairtight manner while a vacuum is applied or during the flow of apressure medium. In doing away with parts to convey the flexible objectthrough the apparatus, the construction of the latter is very simple.Our apparatus ensures a simple, fast, and fool-proof operation. It doesnot require the attendance by skilled labor, nor does it require carefulhandling. It is well suited to be handled in a rough manner, as isnecessary in the case of tying grain sheaves, cement sacks, or similarlyheavy goods. The passage of the flexible object through the loop-shapedtubing, just as the passage of the goods to be tied through the coils ofthe tubing, requires practically no time. There is no longer any wearsince such parts as have been used heretofore to move the flexibleobject are eliminated. Our apparatus is suited for use in high-speedpacking machines and can also be used for the tying together of two endsof single or two flexible objects.

It will be apparent that while we have shown and described our inventionin a few forms only, many changes and modifications may be made withoutdeparting from the spirit of the invention defined in the appendedclaims.

We claim:

1. Apparatus for tying knots with threads, strings, cords, or the likeflexible objects, including a tubing of loop shape to conform to an openembryo form of the knot to be tied and serving to lengthwise receive theflexible object, the open embryo form being assumed by the flexibleobject before the latter is tautened to actually form the knot, theloop-shaped tubing being provided with a single continuous slit alongits inner periphery, sealing means provided on the outside of the tubingto normally keep said slit closed in a gastight manner, and an air pumpcommunicating with the tubing to deliver an air stream to transport theflexible object through the tubing.

2. The apparatus according toclaim 1, wherein the loop-shaped tubingconsists of two detachable sections, one section having an entrance endto receive the flexible object, the other section having an exit end todischarge the flexible object, and wherein a tube is joined to theentrance end, and another tube is joined to the exit end.

3. Apparatus for tying square knots with threads, strings, cords, or thelike flexible objects, including two tubings of loop shape to conform toan open embryo form of the knot to be tied, each tubing serving tolengthwise receive one of two flexible objects used to form the knot,the open embryo form being assumed by the two flexible objects beforethe latter are tautened to actually form the knot, each of theloop-shaped tubings being provided with a single continuous slit alongits inner periphery, sealing means provided on the outside of thetubings to normally keep the two slits closed in a gastight manner, andan air pump communicating with the tubing to deliver an air stream totransport the flexible objects through the tubings.

In the apparatus according to claim 1, a band of resilient material,provided on the outer surface of the loop-shaped tubing to cover theslit in the manner of a flap valve and to serve as said sealing means.

5. In the apparatus according to claim 1, a slitted sleeve of resilientmaterial, surrounding the loop-shaped tubing and serving as said sealingmeans.

6. In the apparatus according to claim 1, the loopshaped tubing havingan entrance end to receive the flexible object, and an exit end todischarge the flexible ob ject, a vacuum pump serving as said air pumpand being connected to said exit end.

7. In the apparatus according to claim 6, a tube arranged to be movablealong its axis'and to be loosely joined to said exit end, the tubeserving to receive the free end of the flexible object upon the passageof the latter through the tubing, and being interposed between the exitend of the tubing and the vacuum ptunp.

8. In the apparatus according to claim 1, the loopshaped tubing havingan entrance end to receive the flexible object, and an exit end todischarge the flexible object, a tube arranged to be movable along itsaxis and to be loosely joined to said entrance end, the tube serving toguide the flexible object into the loop-shaped tubing.

9. In the apparatus according to claim 8, said guide-in tube having abore'to surround the flexible object tighter in proportion as the tubeis shorter.

10. In the apparatus according to claim 1, the loopshaped tubing havingan entrance end and an exit end and comprising more than oneconvolution, the entrance and exit end being a distance apart from eachother, a loop portion obliquely traversing the space between the tubingends, said distance being such as to allow the part of the flexibleobject emerging from said loop portion to continue unobstructedly.

References Cited in the file of this patent UNITED STATES PATENTS876,573 Myers Jan. 14, 1908 2,705,656 Shockey Apr. 5, 1955 FOREIGNPATENTS 158,814 Switzerland Feb. 16, 1933

